Officials are probing how a 51-year-old highway bridge came to collapse in the Italian port city of Genoa yesterday, killing at least 26 people and injuring 16 others as it sent dozens of vehicles tumbling into a heap of concrete and twisted steel.

Budget puts extra $3bn into key roads

The federal budget will include just over $3 billion in additional funding for three key road projects in Brisbane, Melbourne and Sydney.

Transport Minister Anthony Albanese says a record infrastructure spend in Tuesday's budget - equating to about $269 for every Australian - will provide an extra $525 million for Melbourne's M80 project, $718 million for Brisbane's Gateway and $1.8 billion for Sydney motorways.

Mr Albanese says Labor has rectified a "deficit of infrastructure" since coming to office in 2007.

"We have more than doubled the roads budget, increased the rail budget by more than 10 times and we've already committed more to urban public transport than all governments combined previously," he told reporters in Canberra on Monday.